For the fourth volume of Mozart's complete music for keyboard MDG has recorded for the very first time the clavier sonatas K. 15. It is a very rare occurrence when music by Mozart is recorded for the very first time. Mozart's Prelude & Fugue was written "on the fly" during a performance at the home of Baron Bernhard van Swieten. Mozart said "The reason I wrote this was because I had already done the Fugue and written it out while I was working the Prelude out in my head." Siegbert Rampe performs the sonatas on a fortepiano that was built in Mozart's time by Mozart's favorite piano builder.